Non-invasive monitoring of heavy metals in reptiles

Reptilian species show a high susceptibility to exposure to heavy metals chronically occurring in soils and sediments of areas affected by human activities like mineral extraction. This happens, among other causes, because of their frequent, accidental soil ingestion, their close contact to contaminated substrates, or their difficulty to move to pollutant-free zones. Therefore, reptilian monitoring in these polluted areas can be an early indicator of exposure risks to other wildlife groups. In this study, we analyzed the exposure of Mediterranean pond turtles from mining areas of southern Ciudad Real to lead (Pb) and mercury (Hg) in order to validate the use of feces and detached epidermal pieces of carapace scutes as non-invasive methods for metal biomonitoring. This model species, besides the general features abovementioned for reptiles, has an especially high exposure risk to chronic pollution because of its long lifespan. We detected comparatively high blood concentrations, as compared to populations from other mining areas, of Pb and Hg in populations from the former mining districts of Sierra Madrona- Alcudia Valley and Almadén, respectively. Animals from the site most affected by Pb showed evidence of oxidative stress, a usual response to exposure to metals and other environmental pollutants. The comparison of metal concentrations measures in the different sample types revealed the validity of the assessed non-invasive methods as indicator of Pb absorption, whereas the usefulness of these non-invasive samples to monitor Hg in reptiles seems scarce.

Ortiz-Santaliestra ME, Rodríguez A, Pareja-Carrera J, Mateo R, Martinez-Haro M (2019) Tools for non-invasive sampling of metal accumulation and its effects in Mediterranean pond turtle populations inhabiting mining areas,

Full text available until July 12, 2019: